Technique for testing pipe couplings for defects

Abstract

A method and apparatus for testing a new pipe coupling for a leak that could be too small to be detected visually involves a section of pipe, a hole through the pipe, a 90 degree ell affixed to the hole from inside the section of pipe, a length of tubing from the 90 degree ell extending to a tee outside the section of pipe, an air gage attached to the tee, and a tire pump attached to the tee for applying about 100 psi of air pressure to the interior of such pipe coupling through the hole to a small space between the section of pipe and the coupling, for locating a leak in the coupling after first sealing the pipe coupling to the pipe section, as done by observation at the air gage of a decrease in air pressure at such small space.

What is claimed is: 
     
       1. An apparatus for testing a pipe coupling that is to be used for sealing a part of a pipe, comprising: a section of pipe, with an inside surface and an outside surface, with a length longer than said pipe coupling to be tested, and having two ends;   means to define an opening in said length of pipe at a predetermined location intermediate said two ends;   said opening extending through said length of pipe from said inside surface to said outside surface;   nipple means attached to said opening from said inside surface with an outer end of said nipple means mounted within, or surface flush with, said pipe outside surface but not beyond said outside surface of said section of pipe, and extending a predetermined distance into said section of pipe to define an inner end;   a 90 degree ell having two ends, one of which is attached to said inner end of said nipple means, and the other of its two ends pointed toward one end of said section of pipe;   means for mechanically sealing said pipe coupling against said outside surface of said section of pipe;   tube means attached at one end to said other end of said 90 degree ell with a second end of said tube means defining a length extending at least out of said section of pipe;   tee means with three openings, one of its openings attached to said second end of said tube means;   air pressure gage means attached to any one of the remaining openings of said tee means;   adapter means attached to a third of said three openings of said tee means for attaching a source of air pressure.   
     
     
       2. An apparatus as defined by claim 1 wherein said predetermined distance said nipple means extends into said pipe to define said inner end is within the range of 2 to 4 inches. 
     
     
       3. An apparatus as defined by claim 1 wherein said source of air pressure is a hand operable tire pump. 
     
     
       4. A method for testing a pipe coupling for a leak comprising the following steps: selecting a section of pipe longer than said pipe coupling to be tested;   drilling a hole in said section of pipe;   attaching a 90 degree ell to said hole from the inside of said section of pipe;   attaching tube means, having a length of about one-half the length of said section of pipe, to said ell;   attaching a tee means to said tube means at an end furthermost from said 90 degree ell;   attaching air pressure gage means to said tee means;   attaching a source of air pressure to said tee means;   affixing said pipe coupling to be tested to said section of pipe at a location covering said hole;   mechanically sealing said pipe coupling against the outside surface of said section of pipe;   applying air under a pressure, as indicated by said air pressure gage means, of about 100 psi through said tube means and said 90 degree ell to a space between said section of pipe and said pipe coupling; and   observing any pressure decrease at said air pressure gage means to indicate the occurrence of a leak in said pipe coupling.   
     
     
       5. A method as defined by claim 4 wherein each of said attaching steps includes the use of a mechanical union between mated parts accomplished by threading.